Fretted instrument adjusting means



Aug. 11., 1931. A. LARSON 1,313,631

FRETTED INSTRUMENT ADJUSTING IEANS Filed May 2 1930 &

Patented Aug. 11, 1931 PATENT OFFICE AUGUST LARSON, OF CHICAGO, ILLINOIS FRETTED INSTRUMENT ADJUSTING MEANS Application filed May 29,

My invention relates to fretted musical instruments, such as guitars, and more particularly to the method and means of attaching the neck to the body of the instrument,

and my main object is to provide novel means of attachment which are also adjustable to reinforce the neck against the pulling strain of the strings.

A further object of the invention isto embody in the neck unit a reinforcing base which relieves the material of the unit from undue strain that may be imposed by the adjusting means.

Another object of the invention is to so 1:; build the adjusting means that it is controllable from the outside of the instrument body.

A final but nevertheless important objectof the invention is to build the improved instrument with few and rugged connections which are not expensive to manufacture and durable in use.

With the above objects in view and any others that may suggest themselves from the specification and claims to follow, a better understanding of the invention may be had by reference to the accompanying drawings, in which Figure 1 is a longitudinal section, partly in elevation, of the main portion of a fretted instrument, such as a guitar;

Fig. 2 is a section on the line 2-2 of Figure 1;

Fig. 3 is an enlargement taken from Figure 1, but showing a modification in the adjusting means;

Fig. 4 is an enlarged view showing a further modification of the adjusting means;

Fig. 5 is a section on the line 5-5 of Figure 4:;

Fig. 6 is a sectional detail showing the connection for the finger board with the body of the instrument;

Fig. 7 is a fragmental elevation of a rock- 46 able connection between the neck and body of the instrument; and

Fig. 8 is a perspective view of the connec tion shown in Figure 7.

Referring specifically to the drawings, 10

denotes the body of the instrument, 11 the 1930. Serial No. 457,367.

neck and 12 the finger board thereof. Tithin the body, and near the top Ihave pro vided a stay ba'r 13, which is in two parts threaded in each other, as indicated at 13a. The ends of the stay-bar lodge in cavities 10a made in the ends of the instrument body, the stay-bar ends being reduced to provide shoulders for the stay-bar, and these shoulders bearing against lining plates 14. By turning either stay-bar section in the proper direction, the stay-bar may be expandci'l to bear firmly against the ends of the instrument body and so check collapsing tendencies thereof. A nut 15 secures the adjustment of the stay-bar sections.

The neck 11 of the instrument which carries the finger board 12, is designed to be rockable relative to the body of the instrument. It is, however, attached to the latter as shown in Figure 6. Here it is seen that the top of the instrument body is rein forced with an internal block 16 in which is lodged a nut 17 made with a peripheral groove to receive a locking screw 17a. The inner end of the finger board 12 receives a screw 18 which is directed into the nut 1.7 to secure the finger board to the instrument body. This connection is, of course, adjustable to relieve strain or impart the proper position to the finger board; and one or more washers 19 may be interposed between the finger board and the nut to set an adjustment. The fastening just described is more in the nature of an anchor than a rigid assembly, since some flexibility is re quired in the finger board to allow for the rockable movement intended for the neck 11. This flexibility is to some extent afforded by the diaphragm-like nature of the thin top 10a of the instrument body.

It is well known that the pull of the strings draws upon the instrument neck with a buckling tendency, causing the instrument to warp and the strings to lose their pitch. It is therefore advisable to counteract the pulling action of the strings by drawing the neck downwardly. I accomplish this action indirectly by drawing inwardly upon the base 11a of the neck. As clearly shown in Figure 1, I embed a metal pin 20 vertically in such base, extending an eye 21 downwardly from the pin. In the lower portion of the instrument body, I dispose a longitudinally directed rod 22, both of whose ends are threaded. The rod passes through the tail portion of the instrument body to receive a nut 23 and through the opposite end for the eye 21, receiving a nut 2%: be fore the eye, a nut 25 after the same, and afinal or lock nut 26 beyond the nut 25. It will be seen that by manipulating the nuts 24 and 25 in the proper direction, a drawing or repelling action may be imparted to the neck base 11a, and after an adjustment is fixed it may be secured by the lock nut 26. The rod 22 may be secured from turning by suitable means, but I irefer the means shown in Figures 1 and 2. Here it is seen that the rod is cut flat from both sides as shown in Figure 2, and that the corresponding plate 14 is divided with two forks straddling the flattened portion of the rod as clearly indicated in Figure 2. With the plate 14 secured to the instrument end by screws 221), it serves as a positive locl to prevent the turning of the rod 22 while the nuts at its ends are manipulated. The rod 22 therefore serves as the means to draw the neck away from the pull of the strings.

Figure 3 shows a modification of the adjusting means just described, wherein the rod 22 is shortened to the length of a screw, as indicated at 220. This screw receives nut 2? inside the instrument body. lVhen the screw has been tightly threaded through the body wall and the nut 27 firmly secured, the screw may be considered as sutliciently rigid for the purpose of drawing the neck as described. Figures 4- and 5 show a further modification of the adjusting means. Here a bolt 28 is directed from the neck freely through the pin 20 and into nut reinforcement 29 of the instrument body, a. key screw 29a and a lock nut 30 being used on the inside to secure the reinforcement 29 against loosening. The head 28a oi the bolt 28 bears against a metal washer 31, and has a slot 287) for the application of a screw driver to advance or retract the bolt relative to the nut reinforcement This action is intended to vary or adjust the direct spacing of the neck base from the instrument body at a point of medial height. Actually, the assembly of the neck base tenon and the instrument body mortise is a close one, but the spacing apparent in t is intended for a clearer view of the element entering into the assembly. it the top, the neck base end receives screws 32 whose heads are backed by washers 32a of hard material; and between the screws the tenon of the neck base receives a similar screw 33a. The top rim of theinr ument body is reinforced at the site of rare mortise by a fibre or ivory strip 33?). in

registration with the screws 32 and 330-- which are substantially alined, as seen in Fig. 5the strip 336 and the body rim portions adjacent to it are bored with frontal cavities to receive the respective screws with an easy fit, the cavity in the strip 336 being seen in Figure l as an example. The line of screws furnishes a horizontal pivot for the neck as against the instrument body and also squares the neck base from lateral play relative to the latter, the hard strip 33?) and washers 32a protecting the wood parts from yielding to the pressure of the screws. Here it may be added that the neck is also anchored against lateral play by the connection of the screw 18, previously described. At the bottom, another screw 34; is employed, this screw, however, being threaded through the pin 20 and adjusted to bear against the end of the instrument Thus, it has the function of a set body. screw to fix the adjustment of the bolt 28. The latter is prevented from receding relative to the neck base 11a by being annularly grooved as indicated at 280 next outside the end of the neck base which faces the instrument body. Here the neck base tenon 33 receives a facing plate 35 and a slide plate 36 in intimate succession. These plates are apertured as indicated at 37 to receive screws 38 when the plates are positioned as shown. However, the slide plate 36 has a downwardly tapered hole 88a through which the bolt 28 passes, the upper portion of the hole being large enough to permit the passage of the bolt while the lower one being only large enough to accommodate the grooved portion 280 thereof. Thus, 111 assembling the plates, the slide plate 36 1s first positioned low in order to allow the,

pasrage of the bolt. When the groove 280 has assumed the position opposite the slide plate, the latter is raised as indicated in Figure 5 to engage the-grooved portion with the smaller end of the hole 38a, thereby locking the bolt from retraction relative to i rockable connection between the instrument body and the neck is shown in Figures 7 and 8. Here it will be noted that the top corner of the body is reinforced by a metal strip whose terminal portions have downward wings a1. Between these are the sides 42 of a strap 43 which seats in a cavity 44; of the neck base 11a and has ends 45 applied to the base of the cavity. Screws a6 are applied by way of the ends 45 and the wings l1 and directed to the ends of the instrument body, whereby to secure the assembly of the strip 40 and the strap 43 to the latter. The finger board 12 now receives a reinforcing strip 47 from the bottom, the inner end of this strip being secured to the instrument body by a screw 48 or by the manner oi. the screw 18 and the outer end being formed with a hook 170., which straddles medially cut-down portions 4:34; of the strap 43. The instrument neck is thus rockably disposed relative to the assembly of the strip 40 and strap L3, which assembly is rigidly secured to the instrument body as before explained. Thus, the instrument neck is flexible or floats in a sense, and its base may be secured with any of the connections or adjusting means hereinbefore described to alter and fix its angle.

It will be seen that the means described for the disposal and adjustment of the instrument neck relative to the body are posi tive and involve simple and sturdy connections. The adjustments may be made without particular skill, and serve to maintain the instrument neck in proper position for indefinite periods without frequent attention or adjustment.

I claim:

1. Adjusting means for the neck base of a musical stringed instrument relative to the body of the latter comprising, a bolt from the medial portion of the neck base threaded into the body wall to secure and adjustably space the neck from the body, the latter having medial and lateral facial cavities near the top, and medial and lateral screws directed from the upper part of the neck base to seat wit-h their heads loosely in said cavities and constitute a pivot for the neck base during the adjusting action of said bolt.

2. The structure of claim 1, and 'liacings of hardmaterial backing the heads of the screws.

3. The structure of claim 1, and a strip of hard material laid medially in the top rim of the instrument body and formed with a cavity for the medial screw.

4. The structure of claim 1, and a screw directed from the lower portion of the neck base against the body to lock said adjustment.

5. Adjusting means for the neck base of a musical stringed instrument relative to the body of the latter comprising, a bolt directed from the neck base and screwed into the body, said bolt having an annular groove next outside the neck-base end which is opposite the body, and a plate on said end and having a hooked portion engageable with said groove to lock the bolt from longitudinal motion relative to the neck base.

6. Adjusting means for the neck base of a musical stringed instrument relative to the body of the latter comprising, a bolt directed from the neck base and screwed into the body, said bolt having an annular groove next outside the neck-base end which is opposite the body, a plate on said end and having an opening for the passage of the bolt, said opening tapering toward one end and said plate being shiftable to engage the grooved portion of the bolt in the small end of the opening whereby to anchor the bolt from endwise motion relative to the neck base, and means for fastening the plate to the latter in anchoring position.

7. Adjusting means for the neck of a stringed musical instrument comprising, a tapped block built into the top of the instrument body, a screw directed from the inner end of the finger board into the block whereby to anchor such end to the top of the instrument, pivot means between the upper portion of the neck base and the instrument body, and means to control and set the pivotal relation between the latter and the neck base.

8. The structure of claim 7, and spacing means applicable to the screw to adjust the finger board relative to the top of the instrument body.

9. The structure of claim 1, and a strip of hard material laid medially in the top rim of the instrument body and formed with a cavity for the medial screw, and said adjusting means passing freely through the core.

10. The structure of claim 1, and a strip of hard material laid medially in the top rim of the instrument body and formed with a cavity for the medial screw, and a locking screw directed from the neck base against said body end, the locking screw being threaded through the core.

In testimony whereof I affix my signature.

AUGUST LARSON. 

